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map vs foreach 2023
(version: 0)
Benchmark.js
Comparing performance of:
map vs foreach
Created:
2 years ago
by:
Guest
Go to the latest result
Tests:
map
let myArr = ["69", "108", "122", "101", "114", "111"], result = myArr.map((item) => String.fromCharCode(item)).join(""); console.log(result);
foreach
let myArr = ["69", "108", "122", "101", "114", "111"], result = ""; myArr.forEach((item) => (result += String.fromCharCode(item))); console.log(result);
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
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Test case name
Result
map
foreach
Fastest:
N/A
Slowest:
N/A
Latest run results:
Run details:
(Test run date:
2 years ago
)
User agent:
Mozilla/5.0 (Linux; Android 10; K) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Mobile Safari/537.36
Browser/OS:
Chrome Mobile 120 on Android
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<iframe src="https://measurethat.net/Embed?id=494242" width="100%" height="500px"></iframe>
foreach
27K/s
map
26K/s
View exact numbers
Test name
Executions per second
✓
foreach
27,223 Ops/sec
map
26,239 Ops/sec
Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
Let's break down the provided benchmark and explain what's being tested, compared, and the pros/cons of each approach. **Benchmark Overview** The benchmark compares two approaches for mapping over an array of characters: `map()` and `forEach()`. The test case uses a predefined JavaScript array containing ASCII values of characters, which are then converted to their corresponding Unicode characters using `String.fromCharCode()`. **Options Being Compared** 1. **`map()`**: This method returns a new array with the results of applying the provided function on every element in this array. 2. **`forEach()`**: This method executes the provided callback function once for each element in an array. **Pros and Cons** * `map()`: Pros: + Returns a new array, which can be more efficient if you need to use the result later. + Allows for more concise code, as it returns a value directly. Cons: + Creates a new array, which can lead to memory overhead if working with large datasets. + May not be suitable for operations where side effects are expected (e.g., modifying the original array). * `forEach()`: Pros: + Does not create a new array, making it more memory-efficient for large datasets. + Suitable for operations where side effects are expected. Cons: + Returns `undefined`, which may require additional processing to access the result. **Library and Special JS Features** In this benchmark, no specific libraries or special JavaScript features are used. The test case relies solely on built-in JavaScript methods (`map()`, `forEach()`, and `String.fromCharCode()`). **Other Considerations** When choosing between `map()` and `forEach()`, consider the following: * Use `map()` when you need to process an array to produce a new array, or when you want to return a value directly. * Use `forEach()` when you need to execute a callback function for each element in an array, such as iterating over an array without modifying it. **Alternatives** If you're looking for alternative approaches to map over arrays, consider: 1. **`Array.prototype.reduce()`**: Similar to `map()`, but returns a single value (the accumulator) instead of an array. 2. **`for...of` loop**: An older approach to iterating over arrays, which can be more concise but less efficient than `forEach()` or `map()`. 3. **Using `Array.prototype.filter()` and `Array.prototype.slice()`**: If you need to filter out elements from the original array, consider using `filter()` and then slicing the resulting array. Keep in mind that these alternatives may have different performance characteristics and use cases compared to `map()` and `forEach()`.
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